1. Field of the Invention
The present invention relates to dishwashing appliances and somewhat more particularly to spray devices having intermittently operating spray nozzles in such appliances.
2. Prior Art
Dishwashing appliances having rotatable spray devices located in operative relation with dish-supporting racks and which include nozzles for directing water from within the spray devices against dishes, pots, pans, silverware, etc. in the racks within the washing chamber of the appliance are known.
Generally, every nozzle on a spray device is oriented to provide a predetermined spray pattern and at least one nozzle on such a spray device is oriented for directing washing liquid against a silverware basket mounted adjacent the door of a dishwashing appliance. However, since the spray device rotates 360.degree. and the silverware basket occupies an area encompassed by about one-quarter revolution, the silverware washing nozzle directs its water against the washing chamber walls for about three-quarters of a revolution and does not materially contribute to the washing of dishes, etc. within the washing chamber. In addition, dishes, etc. located in corners or other isolated areas of a washing chamber having washing liquid distributed over them only at periodic portions of a revolution by a spray device and at other portions of the revolution are not being sufficiently washed.
Some attempts have been made by the prior art to achieve a somewhat improved water distribution by spray arm nozzles onto dishes in a washing chamber. For example, U.S. Pat. Nos. 3,160,164 and 3,447,752 disclose relatively complex apparatuses for periodically reversing the direction of rotation of a spray device by selectively channeling the flow of washing liquid through the spray device via various mechanical means. However, these devices, aside from their complexity and cost, still have a portion of the washing liquid directed against washing chamber walls and not materially contributing to washing of silverware, isolated dishes, etc. within the chamber.
In addition, various lawn sprinkling apparatuses are known which include means for selectively varying the water distribution pattern. For example, U.S. Pat. No. 3,104,818 discloses a lawn sprinkler having a manifold which may be indexed to various positions for controlling the supply of water to various parts of the sprinkler and thus effecting the water distribution pattern. Lawn sprinklers are quite different from dishwashing appliances and fail to provide intermittently operating nozzles.